The Dilucot method - A clear shot at an excellent edge
Last updated on: 2011-03-21 22:56
The Dilucot method is indubitably my favorite method to hone a straight razor.
At least 9 out of every 10 razors I hone go through the Dilucot procedure. The vast majority of them are returned to the owner without needing any additional treatment. It hasn't always been that way. I was lucky that my very first attempt to try the basic idea behind the Dilucot method delivered jaw dropping results. It took me quite some time afterwards to copy those first results, but that very first success kept me going.
From all the honing paradigms present on www.coticule.be, this one is the most adventurous. You need to learn the particular vernacular of your Coticule: how it speaks though the razor held by your fingers. It's not all that difficult, but do expect it to take some time before you can figure out the optimized procedure for your particular Coticule.
In its very essence, the Dilucot method is one of Zen-like simplicity. One starts out on a Coticule with slurry, and hones till the keenness reaches its limit. At that point the honing goes on, while drops of water are added at intervals, with the intention to slowly wash the slurry down to plain water. That is all there is to it.
It does not take very long to do, and even if you don't always manage to reach the same flabbergasting results, you'll still end up with a razor that caries an impeccable cutting bevel, only in need of little extra work. For that you can divert straight into the final (taped) stages of the Unicot method, or into the progressive honing method, which ever you prefer. But if you take the time to learn how to listen to your honing stone and learn how to play it well, you'll get edges that leave absolutely nothing to be desired.
Why does it work?
For ample abrasion Coticules need to be used with slurry during the first important stages of reestablishing flat bevel faces on the cutting edge of the razor and undo the small damage at the very edge, that's inherent to every dulling process. While sharpening, the garnets in the slurry remove steel of the bevel faces, with a refining of the edge as result. At the same time, the garnets also have a slight detrimental effect on the very tip of our cutting bevel, which obviously influences the keenness in a negative way. As the edge becomes increasingly delicate during the sharpening process, it also becomes less resilient against the impact with the garnets in the slurry. Eventually the edge will start to loose as much as it gains, and from that point onwards we could hone the razor into oblivion without it ever becoming sharper.
On the other hand, when used with only water, the garnets stay locked into the hone's surface, only partially protruding. The keenness barrier rises to well above the nominal level needed for a superb shaving edge. Unfortunately, a Coticule, when used with only water on top, performs extremely slow. Too slow to successfully refine the edge left by the slurry within any reasonable time frame. That's where the dilution phase comes in. If we gradually wash away the slurry with drops of water, the Coticule will progressively slow down, yet at the same time the keenness barrier will rise. The whole process can metaphorically be compared to catching a catfish (not that I know much about fishing). You have to carefully bring the edge home, without breaking the line of keenness.
An entire Dilucot can be divided in 3 stages:
1. Bevel correction.
An edge can't develop keenness on a hone before both sides of the cutting bevel are completely flat all the way up to very edge. It is of equal importance that the edge is free from damage, that accumulates at a microscopic level from the impact with coarse beard hairs.
During bevel correction stage, we deal with these issue. The Coticule is used in its fastest mode: with a slurry of milky consistency, and with "halfstrokes". These are diagonal honing strokes, performed back and forth, without flipping the razor. A finger rests on top of the razor and exerts a mild pressure. Measured with the razor on top of a zeroed kitchen scale the exerted pressure is 250-330g (8.8-12oz). Work with sets of 20-30 halfstrokes, flip the razor (turn it over the spine) and copy the same amount of halfstrokes. The slurry will turn gray. This is a sign that steel particles enter the mixture and doesn't pose any disadvantage. The easiest way to know when done, is to dull the edge up front, slightly below shaving arm hair level. One stroke over a glass object (a beer bottle works very well), with the edge down and no more pressure than the weight of the razor, will do the trick. If your arm hair is very dense and easy to shave, it might be necessary to repeat this "downstroke" a second time. It takes about one set of halfstrokes to undo the effect of a "downstroke", hence any extra sets you need to perform to reach shaving arm hair level again, is work that was required to establish a flat bevel in the first place. The bevel stage is completed, beyond any suspicion, once the razor shaves arm hair along its entire length. There's no real need for the TNT or TPT, albeit both are excellent methods to probe the edge,though difficult to read without experience.
There are two caveats:
A. Razor sharpening demands a stable honing stroke that secures an even contact between the razor and the surface of the whetstone. It takes some practice to adopt a satisfactory honing stroke. Aim for precision rather than speed. Speed comes naturally as you gain experience.
B. It's absolutely imperative that you keep the slurry from becoming to dense or dry. While such a slurry may remove steel at a fast rate, the effect on the very edge is that of pushing it through thick mud. You could reduce the width of the razor considerably without ever reaching a keenness that allows to shave arm hair. Bear in mind, that "the next good bevel" never lies far behind the original bevel. Unless there is visual damage to be honed out, the new bevel will not cause a visual narrowing of the blade. To keep the slurry within limits, add a drop of water at the first signs of dehydration. It's no problem to err on the thin side, while erring on the thick side can be an exercise in frustration.
2. The dilution stage
There's no need to refresh the slurry, provided that some of it is still present on the hone at the end of the bevel stage.
The honing stroke remains the same, only reduce the stroke count per set to 15 back and forth motions. Pressure remains the same as during the bevel correction stage. This is by far the most effective way to proceed through the dilution stage, that I've found so far.
To add the water, don't use a spray bottle, as this offers poor control over the dilution rate. Simply keep a cup of clear water at hand. One "finger load" of water is a good starting point. The means: dip the digit of one finger into the cup and immediately transfer the water that drips off onto the middle of the Coticule. Don't worry about mixing it with the present slurry. That will happen automatically.
It might be necessary to use more water, depending on your Coticule, it's size and the climate you're working in. Now is the time to "listen" to the hone: with every dilution, the abrasive feedback of the Coticule will diminish, till it reaches about the same level as what you get when you use plain water. The catch is this: dilute too fast and you're edge will stay behind. Allow the slurry to become dryer and your edge will revert to a previous keenness limit. In quickly drying conditions, it can be necessary to add a drop of water at the turning point as well, but normally this won't be necessary.
How many dilution steps, varies from Coticule to Coticule, but there no real downside at moving slow. 10-15 steps is a good starting point. Later on, with more experience and being acquainted with your Coticule, you might be able to reduce this to 7-10 steps.
At the end of the dilution stage, add a good splash of water, without actually cleaning the hone and perform another dual set of halfstrokes. Next, clean the hone and razor under a running tap and perform your last dual set of halfstrokes. Time to finish.
3. The finishing stage
Rinse the Coticule and razor well. Perform 30-50 X-strokes without any significant pressure. That's it.
Success can be measured with a HHT. The razor should be able to easily sever a clean, thick hair at 15mm (1/2") from the holding point.
A freshly honed Coticule edge really needs to be stropped well, as the improvement that can be expected from a good stropping is typically larger than that on most other types of hones. This improvement can be clearly monitored with the HHT, that will step up 1 or 2 points on the HHT-performance scale. For this first stropping after honing, I recommend 60 laps on a good linen and 60 laps on leather. For maintenance stropping prior to each shave, 20 linen and 40 leather should be sufficient.
Some additional remarks.
When you're inexperienced with razor sharpening, it might be wise to start out on full hollow razors. They generally carry smaller bevel faces, which are easier and notably quicker to hone.
Aim to learn yourself a steady and even honing stroke. I'm repeating my advice to start slow, but precise. The speed you see in my honing videos comes slowly. Have you ever seen a professional cook chop a carrot in "brunoise" (little cubes of uniform size)? Everyone can do it, although it take untrained hand an hour to do what the cook does in a minute. Sharpening razors is a very meticulous job. Someone skilled may display a second nature while sharpening a razor, that may look as nonchalance. Nothing could be further from the truth.
Should the Dilucot procedure haplessly not deliver the keenness you were after, you still have a razor with a flawless bevel and a perfect candidate for the final (taped) stage of the Unicot procedure.